Underfill material flow control for reduced die-to-die spacing in semiconductor packages

ABSTRACT

Underfill material flow control for reduced die-to-die spacing in semiconductor packages and the resulting semiconductor packages are described. In an example, a semiconductor apparatus includes first and second semiconductor dies, each having a surface with an integrated circuit thereon coupled to contact pads of an uppermost metallization layer of a common semiconductor package substrate by a plurality of conductive contacts, the first and second semiconductor dies separated by a spacing. A barrier structure is disposed between the first semiconductor die and the common semiconductor package substrate and at least partially underneath the first semiconductor die. An underfill material layer is in contact with the second semiconductor die and with the barrier structure, but not in contact with the first semiconductor die.

TECHNICAL FIELD

Embodiments of the invention are in the field of semiconductor packagesand, in particular, underfill material flow control for reduceddie-to-die spacing in semiconductor packages and the resultingsemiconductor packages.

BACKGROUND

Today's consumer electronics market frequently demands complex functionsrequiring very intricate circuitry. Scaling to smaller and smallerfundamental building blocks, e.g. transistors, has enabled theincorporation of even more intricate circuitry on a single die with eachprogressive generation. Semiconductor packages are used for protectingan integrated circuit (IC) chip or die, and also to provide the die withan electrical interface to external circuitry. With the increasingdemand for smaller electronic devices, semiconductor packages aredesigned to be even more compact and must support larger circuitdensity. Furthermore, the demand for higher performance devices resultsin a need for an improved semiconductor package that enables a thinpackaging profile and low overall warpage compatible with subsequentassembly processing.

C4 solder ball connections have been used for many years to provide flipchip interconnections between semiconductor devices and substrates. Aflip chip or Controlled Collapse Chip Connection (C4) is a type ofmounting used for semiconductor devices, such as integrated circuit (IC)chips, MEMS or components, which utilizes solder bumps instead of wirebonds. The solder bumps are deposited on the C4 pads, located on the topside of the substrate package. In order to mount the semiconductordevice to the substrate, it is flipped over—the active side facing downon the mounting area. The solder bumps are used to connect thesemiconductor device directly to the substrate.

Processing a flip chip is similar to conventional IC fabrication, with afew additional steps. Near the end of the manufacturing process, theattachment pads are metalized to make them more receptive to solder.This typically consists of several treatments. A small dot of solder isthen deposited on each metalized pad. The chips are then cut out of thewafer as normal. To attach the flip chip into a circuit, the chip isinverted to bring the solder dots down onto connectors on the underlyingelectronics or circuit board. The solder is then re-melted to produce anelectrical connection, typically using an ultrasonic or alternativelyreflow solder process. This also leaves a small space between the chip'scircuitry and the underlying mounting. In most cases anelectrically-insulating adhesive is then “underfilled” to provide astronger mechanical connection, provide a heat bridge, and to ensure thesolder joints are not stressed due to differential heating of the chipand the rest of the system. However, improvements are needed in thematerials used to underfill in such flip chip arrangements.

Newer packaging and die-to-die interconnect approaches, such as throughsilicon via (TSV) and silicon interposer, are gaining much attentionfrom designers for the realization of high performance Multi-Chip Module(MCM) and System in Package (SiP). However, additional improvements inunderfill material technologies are also needed for such newer packagingregimes.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a cross-sectional view of a semiconductor packagehaving an Embedded Interconnection Bridge (EmIB) connecting Die 1(Memory) and Die 2 (CPU/SoC), in accordance with an embodiment of thepresent invention.

FIG. 2 illustrates a plan view of a package layout for co-packaged highperformance computing (HPC) die and high bandwidth memory (HBM) layout,in accordance with an embodiment of the present invention.

FIG. 3 illustrates a cross-sectional view of a semiconductor packageincluding a memory die and a CPU/SoC die disposed on a common substrate,in accordance with an embodiment of the present invention.

FIG. 4 illustrates a cross-sectional view of a semiconductor packageincluding a memory die and a CPU/SoC die disposed on a common substrate,in accordance with an embodiment of the present invention.

FIG. 5 is a schematic layout of copper (Cu) plane and underfill (UF)regions as separated by die-to-die (D2D) spacing, in accordance with anembodiment of the present invention.

FIG. 6 is a schematic layout of copper (Cu) plane and underfill (UF)regions as separated by die-to-die (D2D) spacings, in accordance with anembodiment of the present invention.

FIG. 7 illustrates an exemplary plan view of a layout for copper tracesbetween dies for small fillets, in accordance with an embodiment of thepresent invention.

FIG. 8 illustrates a representative cross-sectional view of a portion ofthe layout of copper traces of FIG. 7, in accordance with an embodimentof the present invention.

FIG. 9 is an image illustrating the use of copper traces/trenches tolimit epoxy fillet, in accordance with an embodiment of the presentinvention.

FIG. 10 illustrates a plan view of a layout of copper traces/trenchesfor use as runaway routes for excess epoxy, in accordance with anembodiment of the present invention.

FIG. 11 includes a plurality of simulation images from simulationresults demonstrating a runaway trench concept, in accordance with anembodiment of the present invention.

FIG. 12 includes a schematic layout of an ink barrier and underfill (UF)regions as separated by die-to-die (D2D) spacing, in accordance with anembodiment of the present invention.

FIG. 13A illustrates a cross-sectional view of a semiconductor packageincluding multiple die coupled with an embedded interconnect bridge(EmIB) and including barriers for controlling underfill material flow,in accordance with an embodiment of the present invention.

FIG. 13B illustrates a cross-sectional view of a semiconductor packageincluding multiple die coupled with an embedded interconnect bridge(EmIB) and including barriers for controlling underfill material flow,in accordance with an embodiment of the present invention.

FIG. 14 illustrates a cross-sectional view of a semiconductor packageincluding multiple die coupled with an interposer and including barriersfor controlling underfill material flow, in accordance with anembodiment of the present invention.

FIG. 15 illustrates a cross-sectional view of a 3D integrated circuitpackage with through-mold first level interconnects and includingbarriers for controlling underfill material flow, in accordance with anembodiment of the present invention.

FIG. 16 illustrates a cross-sectional view of a 3D integrated circuitpackage with through-mold first level interconnects and includingbarriers for controlling underfill material flow, in accordance with anembodiment of the present invention.

FIG. 17 illustrates a cross-sectional view of a coreless substrate withan embedded stacked through-silicon via die and including barriers forcontrolling underfill material flow, in accordance with an embodiment ofthe present invention.

FIG. 18 is a schematic of a computer system, in accordance with anembodiment of the present invention.

DESCRIPTION OF THE EMBODIMENTS

Underfill material flow control for reduced die-to-die spacing insemiconductor packages and the resulting semiconductor packages aredescribed. In the following description, numerous specific details areset forth, such as packaging and interconnect architectures, in order toprovide a thorough understanding of embodiments of the presentinvention. It will be apparent to one skilled in the art thatembodiments of the present invention may be practiced without thesespecific details. In other instances, well-known features, such asspecific semiconductor fabrication processes, are not described indetail in order to not unnecessarily obscure embodiments of the presentinvention. Furthermore, it is to be understood that the variousembodiments shown in the Figures are illustrative representations andare not necessarily drawn to scale.

One or more embodiments described herein are directed to methods andprocesses for control of underfill (UF) flow to reduce die-to-die (D2D)spacing in Embedded Interconnection Bridge (EmIB) based semiconductorpackages and products. Aspects may include one or more of capillaryunderfill, EmIB based structures, silicon interposer based structures,tight die to die spacing, and general products with tight die to diedistance specifications.

To provide context, Embedded Interconnection Bridge (EmIB) technology isbeing used and/or evaluated for high performance computing (HPC) withhigh bandwidth memory (HBM), examples of which are described below inassociation with FIGS. 1 and 2 below. In general, enabling a small(e.g., approximately 100 micron) die to die (D2D) spacing betweencentral processing unit/system-on-chip (CPU/SoC) die and memory die hasproved challenging, an example of which is described below inassociation with FIG. 3.

FIG. 1 illustrates a cross-sectional view of a semiconductor package 100having an Embedded Interconnection Bridge (EmIB) connecting Die 1(Memory) and Die 2 (CPU/SoC), in accordance with an embodiment of thepresent invention. Referring to FIG. 1, the semiconductor package 100includes a first die 102 (e.g., a memory die) and a second die 104(e.g., a CPU or SoC die). The first die 102 and second die 104 arecoupled to an EmIB 106 through bumps 108 and 110 of the first die 102and second die 104, respectively, and bond pads 112 of the EmIB, e.g.,by thermal compression bonding (TCB). The first die 102, second die 104,and EmIB 106 are included with additional routing layers 114, asdepicted in FIG. 1. The additional routing layers may be simple orcomplex and may be for coupling to other packages or may form part orall of an organic package or printed circuit board (PCB), etc.

FIG. 2 illustrates a plan view of a package layout 200 for co-packagedhigh performance computing (HPC) die and high bandwidth memory (HBM)layout, in accordance with an embodiment of the present invention.Referring to FIG. 2, the package layout 200 includes a common substrate202. A CPU/SoC die 204 is supported by the substrate 202 along with 8memory dies 206. A plurality of EmIBs 208 bridge the memory dies 206 tothe CPU/SoC die 204 by C4 connections 210. The die-to-die spacing 212 isapproximately 100-200 microns. It is to be understood that, from atop-down view perspective, the dies 204 and 206 are disposed above theC4 connections 210, which are disposed above the EmIBs 208, which areincluded in the substrate 202.

FIG. 3 illustrates a cross-sectional view of a semiconductor package 300including a memory die 302 and a CPU/SoC die 304 disposed on a commonsubstrate 306, in accordance with an embodiment of the presentinvention. Referring to FIG. 3, the die-to-die (D2D) spacing 308 betweenthe memory die 302 and the CPU/SoC die 304 is approximately 100-200microns. An underfill (UF) fillet material 309 is disposed in the gap308. Bumps 310 of the memory die 302 are located approximately 1millimeter from the edge 312 of the memory die 302. In accordance withan embodiment of the present invention, the resulting region 314 can beused to place a patterned barrier material, as described in greaterdetail below in association with FIG. 4. Additionally, slots in suchbarrier materials (e.g., a copper (Cu) plane) can reduce epoxy filletwidth/keep out zone (KOZ) in region 316.

More specifically, with reference generally to FIGS. 1-3, high costassociated with HBM dice may require testing of the CPU die prior tomemory die attachment. Current CPU underfill processes result in epoxyfillet width that can prevent memory die attachment from being less thanapproximately 200 microns from the CPU die. Initial evaluationsinvolving the use of a barrier on the CPU die sidewall or dams have notbeen successful. Additionally, if all the dies are bonded beforeunderfill, challenges may arise with respect to filling all of the dieswithout forming voids. The main risk appears to derive from merging flowfronts and also very fast edge flows along the small die to diedistances.

In a general approach, in accordance with one or more embodiments of thepresent invention, for a given underfill (UF) epoxy material and processconditions, the UF fillet geometry (e.g., height, width and spread) canbe modulated by controlling the flow of excess epoxy material with theaid of barriers (e.g., use of Cu planes) that are patterned (e.g., withslots) to channel the epoxy material and result in a short fillet width.In one such embodiment, barriers such as a copper traces or trenches areformed with different widths and lengths and their location andorientation are designed depending on the epoxy flow front otherwiseobserved in the absence the barrier. Such slots can be customized fordifferent die sizes and required spacings between dies. In specificalternative embodiments, other barriers such as surface energy barrierscan be rendered more effective if slots and/or trenches are fabricatedalong the length of the ink barrier. Substrate patterning and laserablation are included as suitable methods for fabricating ink barrierslots.

More specifically, in accordance with one or more embodiments of thepresent invention, 100 to 200 micron D2D spacing is achieved byhindering the UF fillet geometry on a CPU die from interfering withplacement of the memory die. The UF spread/bleed does not extend to thememory pad surfaces (e.g., for a distance of approximately 1.1millimeters for a CPU die edge). In a particular embodiment, the regionon the substrate surface between fine pitch bumps on the CPU and memorydie (e.g., approx. 1.3 millimeters) is the area in which a barriermaterial is placed.

As an example of the above, FIG. 4 illustrates a cross-sectional view ofa semiconductor package 400 including a memory die 402 and a CPU/SoC die404 disposed on a common substrate 406, in accordance with an embodimentof the present invention. Referring to FIG. 4, an EmIB structure 405 isincluded in the substrate 406 and couples the memory die 402 and theCPU/SoC die 404. The die-to-die (D2D) spacing 408 between the memory die402 and the CPU/SoC die 404 is approximately 100-200 microns. Anunderfill (UF) fillet material 409 is disposed in the gap 408. Finepitch bumps 410 of the memory die 402 are located approximately 1millimeter from the edge 412 of the memory die 402. In accordance withan embodiment of the present invention, the resulting region 414includes a patterned barrier material layer 418 (e.g., a patternedcopper layer) disposed thereon. In a specific embodiment, as describedin greater detail below, slots formed in barrier material layer 418 canbe used to reduce epoxy fillet width/keep out zone (KOZ), e.g., atRegion A of FIG. 4. Accordingly, FIG. 4 exemplifies control of a CPU UFepoxy fillet proximity to a memory die edge. The control can be achievedby hindering the UF fillet geometry on a CPU die from interfering withplacement of the memory die (e.g., at Region A).

UF epoxy flow along the edge of a CPU die is expected to be faster inthe fine pitch (e.g., 55 or 65 micron) interconnect regions to the EmIBrendering the region to typically exhibit a larger fillet width. As anexample, FIG. 5 is a schematic layout 500 of copper (Cu) plane 502 andunderfill (UF) 504 regions as separated by die-to-die (D2D) spacing 506(e.g., 100-200 micron), in accordance with an embodiment of the presentinvention. Referring to FIG. 5, the Cu plane 502 has with slots 508formed therein and the UF flow has a pattern 510. The left side of FIG.5 illustrates placement of the barrier material (e.g., the Cu plane).The Cu plane 502 extends between two adjacent die, e.g., along the wholelength of a CPU die 505 and, possibly, also under part of an adjacentmemory die.

It is to be understood that slot length and width can be adjusted tominimize the height and width of the epoxy fillet, as shown in FIG. 5.Also, patterns other than slots may be formed in the barrier (e.g.,copper plane) material. Such slots or patterns cut in copper or otherbarrier materials can enable control of UF spread and/or fillet shape orheight in different regions along a die edge. The slots or patterns are,in one embodiment, fabricated using laser ablation to reduce anunderfill keep out zone (KOZ). It is to be understood that the slots orpatterns can be fabricated to have differing shapes, sizes and/ororientations, depending on the specific application.

In an embodiment, the edge of the copper plane 502 acts as a barrier tothe UF epoxy and, in addition, slots can be made in the copper plane to“bleed out” any excess epoxy material that extends outside the dieregion. Referring again to FIG. 5, the UF dispense direction is shown byarrow 512. In a particular embodiment, the UF flows more at fine pitchinterconnect regions at EmIB 550, as depicted in FIG. 5.

In another aspect, in the case of where two CPU die are disposed above acommon substrate, slots in a barrier material may be formed in a chevronpattern and orientation dependent on the direction of UF dispense flow.As an example, FIG. 6 is a schematic layout 600 of copper (Cu) plane 602and underfill (UF) 604 regions as separated by die-to-die (D2D) spacings606 (e.g., 100-200 micron), in accordance with an embodiment of thepresent invention. Referring to FIG. 6, the Cu plane 602 has a firstplurality of slots 608 having a first orientation and a second pluralityof slots 609 having a second, different, orientation formed therein. TheUF flow has a pattern 610. The left side of FIG. 6 illustrates placementof the barrier material (e.g., the Cu plane). The Cu plane 602 is sharedby two CPU die, 605A and 605B and, possibly, also under part of anadjacent memory die. The UF dispense directions are shown by arrows 612and 613. In a particular embodiment, the UF flows more at fine pitchinterconnect regions at EmIB 650, as depicted in FIG. 6. In a particularembodiment, as depicted, chevron slots (608 and 609) are made in the Cuplane and oriented in the respective direction 612 or 613 of UF epoxyflow.

Referring again to FIGS. 5 and 6, slots such as slots 508, 608 and 609,or other geometric patterns, can be formed in a copper plane using anultra-violet (UV) laser ablation process that does not damage anunderlying dielectric material. In an exemplary embodiment, a suitablelaser parameter set includes the use of pulsed wave UV laser ablation ata laser wavelength of approximately 355 nanometers, a power ofapproximately 18 mJ, a frequency (e.g., repetition rate) ofapproximately 32 kHz, a Galvonic speed of approximately 210 mm/s, a spotsize of approximately 8 microns, a beam expansion of approximately 10×(e.g., for a beam diameter of approximately 40 microns. In oneembodiment, performing the laser ablations involves importing a DXF fileof the slot pattern to the laser system, and the galvo directs the laserbeam to ablate copper only at the slot regions.

FIG. 7 illustrates an exemplary plan view of a layout 700 for coppertraces between dies for small fillets, in accordance with an embodimentof the present invention. Referring to FIG. 7, a plurality of coppertraces 702 is coupled with one or more pad 704, 706, 708, 710 providedto avoid lifting. A CPU die 712, a first memory die 714, and a secondmemory die 716 overly the layout 700. The layout depicted can enable atwo-pass process flow where the CPU is underfilled prior to bonding ofthe memory dies. In another embodiment, the layout also enables aprocess flow where all the dies are bonded before underfilling, so longas each of the dies has at least 1 side where free form a neighboringdie to allow for dispensing of UF material.

FIG. 8 illustrates a representative cross-sectional view of a portion ofthe layout of copper traces of FIG. 7, in accordance with an embodimentof the present invention. Referring to FIG. 8, a semiconductor package800 includes a first die 802 having a first overhang 804 adjacent bumps806 and includes a second die 808 having a second overhang 810 adjacentbumps 812. The first and second die are disposed above a packagesubstrate 814 and intervening dielectric layer 816. In one embodiment,the dielectric layer 816 is an Aginomoto build up film (ABF) dielectriclayer. Copper traces 818 are disposed on the dielectric layer 816,between dies 802 and 808. In one embodiment, as depicted, the featuresof the copper traces 818 have a spacing of approximately 20 microns.Narrower feature widths are approximately 20 microns, while widerfeature widths are approximately 50 microns, as depicted. In oneembodiment, the stepping die size is approximately 25 microns largerthan the actual die size on each side. It is to be understood that thetrenches between traces can be made of different widths, heights and/orspacings.

FIG. 9 is an image 900 illustrating the use of copper traces/trenches tolimit epoxy fillet, in accordance with an embodiment of the presentinvention. Referring to image 900, the epoxy fillet is limited toapproximately 60 microns. The extent of the limiting is sufficient toenable 100 micron die-to-die distance. That is a keep out zone (KOZ) ofless than 100 microns is achieved using copper (Cu) traces.

FIG. 10 illustrates a plan view of a layout 1000 of coppertraces/trenches for use as runaway routes for excess epoxy, inaccordance with an embodiment of the present invention. Referring toFIG. 10, the layout 1000 includes a plurality of copper traces 1002(note that the traces can alternatively be viewed as trenches formed incopper). The copper traces 1002 provide runaway routes for excess epoxywhen dispensed on the die 1004 located on the right side of the layout1000. In one embodiment, the spacing between the traces 1002 isdetermined such that the capillary pressure (pull) is higher than thedie bump area 1006. This results in excess epoxy being sucked by therunaway traces, away from the die edge, keeping the fillet small.Referring back to FIG. 7, such traces are implemented between dies.

FIG. 11 includes a plurality of simulation images 1100 from simulationresults demonstrating a runaway trench concept, in accordance with anembodiment of the present invention. Referring to the simulation images1100, at (A), an epoxy 1102 is dispensed on the right side of a die1104. Following images (A)-(H), the epoxy 1102 is pulled under a C4 area1106 of the die 1104. As the fillet grows, it touches the trench on theleft side. The trench continues to pull the excess epoxy with highercapillary force until the fillet is broken on the left side. This leavesthe fillet width smaller than the distance between die and trenches.

In another embodiment, instead of copper, an ink barrier is used. In onesuch embodiment, patterns formed by the ink barrier are greater thanapproximately 150 microns wide. By contrast, features at or less than150 microns in width may be breached during an epoxy flow process. Inone embodiment, in a wider ink barrier (e.g., feature width greater than150 microns) is used together with slots formed in a metal barriermaterial (e.g., in a copper barrier layer) to provide for additionalcontainment of an epoxy flow. In another embodiment, slots are patternedwith relatively wider cavities in regions where the epoxy flow isgreater (e.g., regions where there are fine pitch interconnections).

As an example of an implementation using an ink barrier, FIG. 12includes a schematic layout 1200 of an ink barrier 1202 and underfill(UF) 1204 regions as separated by die-to-die (D2D) spacing 1206 (e.g.,100-200 micron), in accordance with an embodiment of the presentinvention. The UF material 1204 may bleed to a greater extent at finebump structures, as shown in FIG. 12. A second ink barrier 1203 is alsoincluded on the same side of the spacing 1206 as the UF 1204. Alsoincluded in FIG. 12 are magnified views of ink barrier 1202 (as planview 1202A and cross-sectional view 1202B) and of ink barrier 1203 (asplan view 1203A and cross-sectional view 1203B). As viewed from themagnified views, in an embodiment, slots 1250 and 1252 may be includedin the ink barriers 1202 and 1203, respectively. In one such embodiment,slots or patterns in the ink barriers 1202 and 1203 are cut into the inkin order to contain any UF material that breaks the ink barrier height.In a specific embodiment, as depicted in FIG. 12, slots located on theleft-hand side of layout 1200 and connected slots on the right-hand sideof layout 1200 aid in flow of excess UF material and reduction in filletwidth.

Embodiments described herein may have far reaching implementations for,e.g., reliability improvement. Applications may include, but need not belimited to, CPUs/processors, multi-chip/3D packaging including CPU incombination with other devices, memory (e.g., flash/DRAM/SRAM, etc.Several non-limiting examples are provided below. Implementationsinclude applications in high performance microprocessor (e.g., server)packages, multi-chip packages, organic package substrates, transmissionlines, 2.5 D (Si feature between die and board), on-die, on package,etc. architectures. More generally, embodiments described herein mayhave far reaching implementations for CPUs/processors, multi-chip/3Dpackaging including CPU in combination with other devices, memory (e.g.,flash/DRAM/SRAM, etc. Several non-limiting examples are provided below.Application may be particularly useful for flip chip, controlledcollapse chip connection (C4) and/or ball grid array (BGA)implementations.

In a first general example, an example of which is illustrated in FIG.4, in accordance with an embodiment of the present invention, a dies arecoupled to a flexible substrate or a rigid substrate, depending upon thespecific application. The substrate has a plurality of electrical tracesdisposed therein. In an embodiment, an external contact layer is alsoformed. In one embodiment, the external contact layer includes a ballgrid array (BGA). In other embodiments, the external contact layerincludes an array such as, but not limited to, a land grid array (LGA)or an array of pins (PGA). Regions 414 for inclusion of barriers 418 forcontrolling underfill material flow are provided in the packagesubstrate.

In another example implementation, FIG. 13A illustrates across-sectional view of a semiconductor package 1300A including multipledie coupled with an EmIB and each die including barriers for controllingunderfill material flow, in accordance with another embodiment of thepresent invention. Referring to FIG. 13A, the semiconductor package1300A includes a first die 1302 (such as a CPU, memory chipset, etc.)and a second die 1304 (such as a CPU, memory chipset, etc.). The firstdie 1302 and second die 1304 are coupled to an EmIB 1306 through bumps1308 and 1310 of the first die 1302 and second die 1304, respectively,and bond pads 1312 of the silicon bridge, e.g., by thermal compressionbonding (TCB). The first die 1302, second die 1304, and EmIB 1306 areincluded with additional routing layers 1314, as depicted in FIG. 13A.The additional routing layers may be simple or complex and may be forcoupling to other packages or may form part or all of an organic packageor printed circuit board (PCB), etc. An epoxy-fillet material 1349 isincluded between the first die 1302 and the EmIB 1312/structure 1314interface and between the second die 1304 and the EmIB 1312/structure1314 interface. In one embodiment, regions 1301 for inclusion ofbarriers for controlling underfill material flow are provided in thestructure 1314. In another embodiment, a silicon bridge is used and isnot embedded in the package, but rather in an open cavity.

In another example implementation, FIG. 13B illustrates across-sectional view of a semiconductor package 400B including multipledie/die stack coupled with an embedded interconnect bridge (EmIB) andeach die/die stack including barriers for controlling underfill materialflow, in accordance with an embodiment of the present invention.Referring to FIG. 13B, the semiconductor package 1300B includes a firstdie 1352 (such as a central processing unit, CPU) and a second die 1354(such as an additional CPU or a memory die or memory die stack, thememory die stack depicted in FIG. 13B). The first die 1352 and seconddie 1354 are coupled to an EmIB 1356 through bumps 1358 and 1360 of thefirst die 1352 and second die 1354, respectively, e.g., by thermalcompression bonding (TCB). The EmIB 1356 is embedded in a substrate(e.g., flexible organic substrate) or board (such as epoxy PCB material)material 1370, as depicted in FIG. 13B. An epoxy fillet material 1399 isincluded between the first die 1352 and the EmIB 1356/substrate 1370interface and between the second die 1354 and the EmIB 1356/substrate1370 interface. In one embodiment, regions 1351 for inclusion ofbarriers for controlling underfill material flow are provided in thesubstrate 1370.

Embodiments of the present invention may also be applicable for aninterposer structure, either at an interposer/substrate interface, or atdie/interposer interfaces, or both. For example, FIG. 14 illustrates across-sectional view of a semiconductor package 1400 including multipledie coupled with an interposer and including barriers for controllingunderfill material flow, in accordance with an embodiment of the presentinvention. Referring to FIG. 14, the semiconductor package 1400 includesa first die 1402 and a second die 1404. The first die 1402 and seconddie 1404 are coupled to an interposer 1406, such as a siliconinterposer. The first die 1402 and second die 1404 are coupled to theinterposer 1406 through bumps 1408 and 1410 of the first die 1402 andsecond die 1404, respectively, and bond pads 1412 of the interposer1406, e.g., by thermal compression bonding (TCB). The interposer 1406couples the first die 1402 and second die 1404 with an organic package1420. The organic package 1420 may include its own routing layers, asdepicted in FIG. 14. Coupling through interposer 1406 may be achieved byuse of through silicon vias (TSVs) 1430, as is also depicted in FIG. 14.In an embodiment, as depicted, possible locations for including anunderfill material 1497, 1498 or 1498 include between the first die 1402and interposer 1406, between the second die 1404 and interposer 1406,and between the interposer 1406 and package 1420. In one embodiment,regions 1401A for inclusion of barriers for controlling underfillmaterial flow between a die and interposer are provided in theinterposer 1406. In one embodiment, regions 1401B for inclusion ofbarriers for controlling underfill material flow between an interposerand substrate are provided in the organic package 1420.

In another aspect, various 3D integrated circuit packages withthrough-mold first level interconnects and including an epoxy filletmaterial are described, in accordance with embodiments of the presentinvention.

In a first example, referring to FIG. 15, a semiconductor package 1500includes a substrate 1502. A bottom semiconductor die 1504 has an activeside 1506 with a surface area. The bottom semiconductor die 1504 iscoupled to the substrate 1502 with the active side 1506 distal from thesubstrate 1502. A top semiconductor die 1508 has an active side 1510with a surface area larger than the surface area of the bottomsemiconductor die 1504. The top semiconductor die 1508 is coupled to thesubstrate 1502 with the active side 1510 proximate to the substrate1502. The active side 1506 of the bottom semiconductor die 1504 isfacing and conductively coupled to the active side 1510 of the topsemiconductor die 1508 by die to die interconnect structures 1512 (e.g.,composed of soldered bumps from each of the die). The top semiconductordie 1508 is conductively coupled to the substrate 1502 by first levelinterconnects 1514 that bypass the bottom semiconductor die 1504. Thetop semiconductor die 1508 is further conductively coupled to thesubstrate 1502 by a plurality of bumps 1520 (e.g., tall copper bumps)that extend from the active side 1510 of the top semiconductor die 1508and adjacent to the bottom semiconductor die 1504. The plurality ofbumps 1520 is coupled to the first level interconnects 1514. In anembodiment, the bottom semiconductor die 1504 and the plurality of bumps1520 are housed in a molding layer 1516, as depicted in FIG. 15. In anembodiment, the top semiconductor die 1508 and the bottom semiconductordie 1504 are further coupled to the substrate 1502 by an epoxy filletmaterial 1518, as is also depicted in FIG. 15. In one embodiment,regions 1501 for inclusion barriers for controlling underfill materialflow are provided in the substrate 1502.

In an embodiment, the top semiconductor die 1508 is configured toprovide power to the bottom semiconductor die 1504. In an embodiment,the top semiconductor die 1508 is configured to facilitate communicationbetween the bottom semiconductor die 1504 and the substrate 1504, e.g.,through routing in the substrate 1508. In an embodiment, the bottomsemiconductor die 1504 has no through silicon vias (TSVs). Thus,connection between the bottom die 1504 and substrate 1502 is achievedindirectly through interconnect lines on the top die 1508 as well as theFLI bumps 1514. It is to be understood, however, that, in an alternativeembodiment, a bottom die may be connected directly by using TSV on thebottom die.

Thus, in reference to FIG. 15, for a 3D IC with through-mold FLI, bottomand top active die are stacked face-to-face. No TSV may be necessary toachieve such 3D IC stacking FLI copper bumps are embedded in a moldinglayer. The top and bottom die have a common interface underfilled by themolding compound. Fabrication-wise, the final 3D IC stacked die withthrough mold first level interconnect (FLI) is attached to a packagesubstrate, under-filled, and subsequently assembled.

One or both of the semiconductor die 1504 or 1508 may be formed from asemiconductor substrate, such as a single crystalline silicon substrate.Other materials, such as, but not limited to, group III-V material andgermanium or silicon germanium material substrates may also beconsidered. The active side (1506 or 1510, respectively) of thesemiconductor die 1504 or 1508 may be the side upon which semiconductordevices are formed. In an embodiment, the active side 1506 or 1510 ofthe semiconductor die 1504 or 1508, respectively, includes a pluralityof semiconductor devices, such as but not limited to transistors,capacitors and resistors interconnected together by a dieinterconnection structure into functional circuits to thereby form anintegrated circuit. As will be understood to those skilled in the art,the device side of the semiconductor die includes an active portion withintegrated circuitry and interconnections. The semiconductor die may beany appropriate integrated circuit device including but not limited to amicroprocessor (single or multi-core), a memory device, a chipset, agraphics device, an application specific integrated circuit according toseveral different embodiments.

Stacked die apparatus 1500 may be particularly suitable for packaging amemory die with a logic die. For example, in an embodiment, one of die1504 or 1508 is a memory die. The other die is a logic die. In anembodiment of the present invention, the memory die is a memory device,such as but not limited to a static random access memory (SRAM), adynamic access memory (DRAM), a nonvolatile memory (NVM) and the logicdie is a logic device, such as but not limited to a microprocessor and adigital signal processor.

In accordance with an embodiment of the present invention, one or moreof die interconnect structures 1512, plurality of bumps 1520, or firstlevel interconnects 1514 is composed of an array of metal bumps. In oneembodiment, each metal bump is composed of a metal such as, but notlimited to, copper, gold, or nickel. Substrate 1502 may be a flexiblesubstrate or a rigid substrate, depending upon the specific application.In an embodiment, substrate 1502 has a plurality of electrical tracesdisposed therein. In an embodiment, an external contact layer is alsoformed. In one embodiment, the external contact layer includes a ballgrid array (BGA). In other embodiments, the external contact layerincludes an array such as, but not limited to, a land grid array (LGA)or an array of pins (PGA).

With respect to molding layer 1516, several options may be used tofabricate the layer. In an embodiment, an FLI bump and bottom-dieover-mold approach is used. In one embodiment, the over-mold layer issubsequently grinded back to expose the FLI bumps. In one embodiment,grind back is performed close to the bump (e.g., copper bump) and thenlaser ablation is used to open the copper bumps. Subsequently, solderpaste print or micro-ball attach is performed onto the copper bumps. Inone embodiment, directly laser open of the copper bumps is performedwithout any grind back. A solder operation may similarly be performed asabove. In another embodiment, bump and bottom die molding are exposedwith a polymer film above the FLI bumps and bottom die. No bump exposureis needed; however, cleaning of the FLI Cu bump may be needed by plasma,or laser, etc. In another embodiment, transfer or compression mold isused. In another embodiment, capillary underfill layer formation isextended to cover the FLI bumps in instead of conventional molding. Themolding layer 1516 may be composed of a non-conductive material. In oneembodiment, the molding layer 1516 is composed of a material such as,but not limited to, a plastic or an epoxy resin composed of silicafillers.

In a second example, referring to FIG. 16, a semiconductor package 1600includes a substrate 1602. A bottom semiconductor die 1604 has an activeside 1606 with a surface area. The bottom semiconductor die 1604 iscoupled to the substrate 1602 with the active side 1606 distal from thesubstrate 1602. A top semiconductor die 1608 has an active side 1610with a surface area larger than the surface area of the bottomsemiconductor die 1604. The top semiconductor die 1608 is coupled to thesubstrate 1602 with the active side 1610 proximate to the substrate1602. The active side 1606 of the bottom semiconductor die 1604 isfacing and conductively coupled to the active side 1610 of the topsemiconductor die 1608 by die to die interconnect structures 1612. Thetop semiconductor die 1608 is conductively coupled to the substrate 1602by first level interconnects 1614 that bypass the bottom semiconductordie 1604. The top semiconductor die 1608 is further conductively coupledto the substrate 1602 by a plurality of bumps 1620 that extend from theactive side 1610 of the top semiconductor die 1608, and at leastpartially adjacent to the bottom semiconductor die 1604, to a pluralityof solder balls 1622. The plurality of solder balls 1622 is coupled tothe first level interconnects 1614. In an embodiment, the bottomsemiconductor die 1604, the plurality of bumps 1620, and the pluralityof solder balls 1622 are housed in a molding layer 1616, as depicted inFIG. 16. In an embodiment, the top semiconductor die 1608 and the bottomsemiconductor die 1604 are further coupled to the substrate 1602 by anepoxy fillet material 1618, as is also depicted in FIG. 16. In oneembodiment, regions 1601 for inclusion of barriers for controllingunderfill material flow are provided in the substrate 1602.

Thus, in reference to FIG. 16, another approach for a 3D IC withthrough-mold FLI includes disposing solder inside a molding layer. Thesolder may be placed before molding and then exposed by grind back orlaser open. Alternatively, solder paste may be placed after laseropening through copper bumps. The characteristics and configurations ofthe packaged die and the materials of package 1600 may be the same orsimilar to those described above for package 1500. In an embodiment, thesolder balls 1622 are composed of lead or are lead free, such as alloysof gold and tin solder or silver and tin solder.

In reference to FIGS. 15 and 16, mixed FLI bump heights may be used fora top semiconductor die. For example, in one embodiment, a mixed heightFLI bump is created by using a top-hat or a slender copper columnbumping process. Here, the first bumping mask and plating operationprovides short bump heights for both FLI and LMI. The second bumpingmask and plating operation provides only the FLI bumps as taller. It isto be understood that various combinations of copper and solder bumpingmay be performed for FLI, as shown FIGS. 15 and 16.

In another aspect of the present invention, coreless substrates withembedded stacked through-silicon via die are disclosed. For example, asemiconductor die with C4 solder ball connections may be packaged in aBumpless Build-Up Layer or BBUL processor packaging technology. Such aprocess is bumpless since it does not use the usual tiny solder bumps toattach the silicon die to the processor package wires. It has build-uplayers since it is grown or built-up around the silicon die.Additionally, some semiconductor packages now use a coreless substrate,which does not include the thick resin core layer commonly found inconventional substrates. In an embodiment, as part of the BBUL process,electrically conductive vias and routing layers are formed above theactive side of a semiconductor die using a semi-additive process (SAP)to complete remaining layers. In an embodiment, an external contactlayer is formed. In one embodiment, an array of external conductivecontacts is a ball grid array (BGA). In other embodiments, the array ofexternal conductive contacts is an array such as, but not limited to, aland grid array (LGA) or an array of pins (PGA). In a specific exampleinvolving stacked die, FIG. 17 illustrates a cross-sectional view of acoreless substrate with an embedded stacked through-silicon via die andincluding barriers for controlling underfill material flow, inaccordance with an embodiment of the present invention.

Referring to FIG. 17, a stacked die apparatus 1700 includes a first die1702 embedded in a coreless substrate 1704. The coreless substrate 1704includes a land side 1706 and a die side 1708. The first die 1702 alsoincludes an active surface, or device side, 1710 and a backside surface,or backside, 1712 and it can be seen that the active surface 1710 of thefirst die 1702 faces toward the land side 1706 while the backside 1712faces in the same direction as the die side 1708 of coreless substrate1704. The active surface may include a plurality of semiconductordevices, such as but not limited to transistors, capacitors andresistors interconnected together by a die interconnection structureinto functional circuits to thereby form an integrated circuit.

As will be understood to those skilled in the art, the device side 1710of first die 1702 includes an active portion with integrated circuitryand interconnections (not shown). The first die 1702 may be anyappropriate integrated circuit device including but not limited to amicroprocessor (single or multi-core), a memory device, a chipset, agraphics device, an application specific integrated circuit according toseveral different embodiments. In an embodiment, the stacked dieapparatus 1700 also includes a die-bonding film 1730 disposed on thebackside 1712 of the first die 1702.

In an embodiment, the first die 1702 is part of a larger apparatus thatincludes a second die 1714 that is disposed below the die side 1708 andthat is coupled to the first die 1702. The second die 1714 is alsoillustrated with an active surface, or device side 1716 in simplifieddepiction, but it may also have metallization M1 to M11 or any numberand top metallization thicknesses. Second die 1714 also has a backsidesurface, or backside, 1718.

Second die 1714 is also embedded in the coreless substrate 1704. In anembodiment, the second die 1714 has at least one through-silicon via1720. Two through-silicon vias are depicted, one of which is enumerated,but the two illustrated through-silicon vias are presented forsimplicity. In an embodiment, up to 1000 through-silicon vias are foundin the second die 1714. The second die 1714 may therefore be referred toas a die including a through-silicon via disposed therein (TSV die1714). The device side 1716 of the TSV die 1714 faces toward the landside 1706 while the backside 1718 faces toward the die side 1708 ofcoreless substrate 1704. As will be understood to those skilled in theart, the device side 1716 of the TSV die 1714 also includes an activeportion with integrated circuitry and interconnections (not shown). TheTSV die 1714 may be any appropriate integrated circuit device includingbut not limited to a microprocessor (single or multi-core), a memorydevice, a chipset, a graphics device, an application specific integratedcircuit according to several different embodiments.

As depicted, the first die 1702 is coupled to the TSV die 1714 thoughthe at least one through-silicon via 1720. In an embodiment, the firstdie 1702 is electrically coupled to the TSV die 1714 through the one ormore through-silicon vias. In one embodiment, the first die 1702 iselectrically coupled to the TSV die 1714 through the one or morethrough-silicon vias 1720 by one or more corresponding conductive bumps1726 disposed on the first die 1702 and by one or more bond pads (notshown) disposed on the TSV die 1714. The bond pads are included on thebackside 1718 of TSV die 1714 and in alignment with the one or morethrough-silicon vias 1720. In an embodiment, a layer of epoxy fluxmaterial 1728 is disposed between the first die 1702 and the TSV die1714. In an embodiment, the coreless substrate 1704 is free fromadditional routing layers between the first die 1702 and the TSV die1714. That is, in an embodiment, the first die 1702 and the TSV die 1714communicate solely through conductive bumps on the device side 1710 offirst die 1702 and the one or more through-silicon vias 1720 of TSV die1714.

The TSV die 1714 is also illustrated with a metallization on device side1718 in simplified form. The metallization is in contact with theintegrated circuitry in the TSV die 1714 at the device side 1716. In anembodiment, the metallization has metal-one (M1) to metal-eleven (M11)metallization layers in order to pin out the complexity of the TSV die1714 to the outside world, where M1 is in contact with the integratedcircuitry in the TSV die 1714. In selected embodiments, any number ofmetallizations between M1 and M11 are present. In an example embodiment,the TSV die 1714 has metallizations from M1 to M7 and M7 is thicker thanM1 to M6. Other metallization numbers and thickness combinations may beachieved depending upon a given application utility.

In an embodiment, as depicted in FIG. 17, stacked die apparatus 1700includes a foundation substrate 1722 at the land side 1706 of corelesssubstrate 1704. For example, where the first die 1702 and TSV die 1714are part of a hand-held device such as a smart phone embodiment or ahand-held reader embodiment, the foundation substrate 1722 is amotherboard. In an example embodiment, where the first die 1702 and TSVdie 1714 are part of a hand-held device such as a smart phone embodimentor a hand-held reader embodiment, the foundation substrate 1722 is anexternal shell such as the portion an individual touches during use. Inan example embodiment, where the first die 1702 and TSV die 1714 arepart of a hand-held device such as a smart phone embodiment or ahand-held reader embodiment, the foundation substrate 1722 includes boththe motherboard and an external shell such as the portion an individualtouches during use. In an embodiment, coreless substrate 1704 is furthercoupled to the foundation substrate 1122 by an underfill material 1799(e.g., an epoxy underfill material), as is also depicted in FIG. 17. Inone such embodiment, regions 1701 for inclusion of barriers forcontrolling underfill material flow are provided in the foundationsubstrate 1722.

An array of external conductive contacts 1732 is disposed on the landside 1706 of the coreless substrate 1704. In an embodiment, the externalconductive contacts 1732 couple the coreless substrate 1704 to thefoundation substrate 1722. The external conductive contacts 1732 areused for electrical communication with the foundation substrate 1722. Inone embodiment, the array of external conductive contacts 1732 is a ballgrid array (BGA). A solder mask 1734 makes up the material that formsthe land side 1706 of the coreless substrate 1704. The externalconductive contacts 1732 are disposed upon bump bond pads 1736.

FIG. 18 is a schematic of a computer system 1800, in accordance with anembodiment of the present invention. The computer system 1800 (alsoreferred to as the electronic system 1800) as depicted can embody apackage substrate having barriers for controlling underfill materialflow according to any of the several disclosed embodiments and theirequivalents as set forth in this disclosure. The computer system 1800may be a mobile device such as a netbook computer. The computer system1800 may be a mobile device such as a wireless smart phone. The computersystem 1800 may be a desktop computer. The computer system 1800 may be ahand-held reader. The computer system 1800 may be a server system. Thecomputer system 1800 may be a supercomputer or high-performancecomputing system.

In an embodiment, the electronic system 1800 is a computer system thatincludes a system bus 1820 to electrically couple the various componentsof the electronic system 1800. The system bus 1820 is a single bus orany combination of busses according to various embodiments. Theelectronic system 1800 includes a voltage source 1830 that providespower to the integrated circuit 1810. In some embodiments, the voltagesource 1830 supplies current to the integrated circuit 1810 through thesystem bus 1820.

The integrated circuit 1810 is electrically coupled to the system bus1820 and includes any circuit, or combination of circuits according toan embodiment. In an embodiment, the integrated circuit 1810 includes aprocessor 1812 that can be of any type. As used herein, the processor1812 may mean any type of circuit such as, but not limited to, amicroprocessor, a microcontroller, a graphics processor, a digitalsignal processor, or another processor. In an embodiment, the processor1812 includes, or is coupled with, reliable microstrip routing for densemulti-chip-package interconnects, as disclosed herein. In an embodiment,SRAM embodiments are found in memory caches of the processor. Othertypes of circuits that can be included in the integrated circuit 1810are a custom circuit or an application-specific integrated circuit(ASIC), such as a communications circuit 1814 for use in wirelessdevices such as cellular telephones, smart phones, pagers, portablecomputers, two-way radios, and similar electronic systems, or acommunications circuit for servers. In an embodiment, the integratedcircuit 1810 includes on-die memory 1816 such as static random-accessmemory (SRAM). In an embodiment, the integrated circuit 1810 includesembedded on-die memory 1816 such as embedded dynamic random-accessmemory (eDRAM).

In an embodiment, the integrated circuit 1810 is complemented with asubsequent integrated circuit 1811. Useful embodiments include a dualprocessor 1813 and a dual communications circuit 1815 and dual on-diememory 1817 such as SRAM. In an embodiment, the dual integrated circuit1810 includes embedded on-die memory 1817 such as eDRAM.

In an embodiment, the electronic system 1800 also includes an externalmemory 1840 that in turn may include one or more memory elementssuitable to the particular application, such as a main memory 1842 inthe form of RAM, one or more hard drives 1844, and/or one or more drivesthat handle removable media 1846, such as diskettes, compact disks(CDs), digital variable disks (DVDs), flash memory drives, and otherremovable media known in the art. The external memory 1840 may also beembedded memory 1848 such as the first die in a die stack, according toan embodiment.

In an embodiment, the electronic system 1800 also includes a displaydevice 1850, an audio output 1860. In an embodiment, the electronicsystem 1800 includes an input device such as a controller 1870 that maybe a keyboard, mouse, trackball, game controller, microphone,voice-recognition device, or any other input device that inputsinformation into the electronic system 1800. In an embodiment, an inputdevice 1870 is a camera. In an embodiment, an input device 1870 is adigital sound recorder. In an embodiment, an input device 1870 is acamera and a digital sound recorder.

As shown herein, the integrated circuit 1810 can be implemented in anumber of different embodiments, including a package substrate havingbarriers for controlling underfill material flow according to any of theseveral disclosed embodiments and their equivalents, an electronicsystem, a computer system, one or more methods of fabricating anintegrated circuit, and one or more methods of fabricating an electronicassembly that includes a package substrate having barriers forcontrolling underfill material flow according to any of the severaldisclosed embodiments as set forth herein in the various embodiments andtheir art-recognized equivalents. The elements, materials, geometries,dimensions, and sequence of operations can all be varied to suitparticular I/O coupling requirements including array contact count,array contact configuration for a microelectronic die embedded in aprocessor mounting substrate according to any of the several disclosedpackage substrates having barriers for controlling underfill materialflow embodiments and their equivalents. A foundation substrate may beincluded, as represented by the dashed line of FIG. 18. Passive devicesmay also be included, as is also depicted in FIG. 18.

Embodiments of the present invention include underfill material flowcontrol for reduced die-to-die spacing in semiconductor packages and theresulting semiconductor packages.

In an embodiment, a semiconductor apparatus includes first and secondsemiconductor dies, each having a surface with an integrated circuitthereon coupled to contact pads of an uppermost metallization layer of acommon semiconductor package substrate by a plurality of conductivecontacts, the first and second semiconductor dies separated by aspacing. A barrier structure is disposed between the first semiconductordie and the common semiconductor package substrate and at leastpartially underneath the first semiconductor die. An underfill materiallayer is in contact with the second semiconductor die and with thebarrier structure, but not in contact with the first semiconductor die.

In one embodiment, the barrier structure includes a plurality of coppertraces disposed on an uppermost surface of the common semiconductorpackage substrate.

In one embodiment, the plurality of copper traces has a chevron pattern.

In one embodiment, the barrier structure includes a patterned inkstructure disposed on an uppermost surface of the common semiconductorpackage substrate.

In one embodiment, the spacing separating the first and secondsemiconductor dies is approximately 100 microns.

In one embodiment, the first semiconductor die is a memory die, and thesecond semiconductor die is one such as, but not limited to, amicroprocessor die or a system-on-chip (SoC) die.

In one embodiment, the barrier structure includes a plurality of slotsto restrict flow of an underfill material used to form the underfillmaterial layer.

In one embodiment, the first and second semiconductor dies areelectrically coupled to one another by an embedded interconnectionbridge (EmIB) disposed within the common semiconductor packagesubstrate.

In an embodiment, a semiconductor package includes first and secondadjacent semiconductor dies separated by a spacing. A silicon interposerstructure is disposed below and electrically couples the first andsecond semiconductor dies. An organic package substrate is disposedbelow and electrically coupled to the silicon interposer structure. Theorganic package substrate includes a plurality of routing layerstherein. A barrier structure is disposed between the first semiconductordie and the silicon interposer structure and at least partiallyunderneath the first semiconductor die. An underfill material layer isin contact with the second semiconductor die and with the barrierstructure, but not in contact with the first semiconductor die.

In one embodiment, the barrier structure includes a plurality of coppertraces disposed on an uppermost surface of the silicon interposerstructure.

In one embodiment, the plurality of copper traces has a chevron pattern.

In one embodiment, the barrier structure includes a patterned inkstructure disposed on an uppermost surface of the silicon interposerstructure.

In one embodiment, the spacing separating the first and secondsemiconductor dies is approximately 100 microns.

In one embodiment, the first semiconductor die is a memory die, and thesecond semiconductor die is one such as, but not limited to, amicroprocessor die or a system-on-chip (SoC) die.

In one embodiment, the barrier structure includes a plurality of slotsto restrict flow of an underfill material used to form the underfillmaterial layer.

In one embodiment, the semiconductor package further includes a secondbarrier structure disposed between the organic package substrate and thesilicon interposer structure.

In an embodiment, a bumpless build-up layer (BBUL) semiconductorapparatus includes a semiconductor die having a backside and a deviceside. A coreless substrate includes a land side and a die side, and thesemiconductor die is embedded in the coreless substrate. The backside ofthe semiconductor die faces the die side of the coreless substrate, andthe device side of the semiconductor die faces the land side of thecoreless substrate. A foundation substrate is included. An array ofexternal conductive contacts is disposed on the land side of thecoreless substrate, electrically coupling the coreless substrate to thefoundation substrate. A barrier structure is disposed between thesemiconductor die and the foundation substrate proximate to thesemiconductor die. An underfill material layer is disposed between theland side of the coreless substrate and the foundation substrate andsurrounding the plurality of external conductive contacts, the underfillmaterial layer in contact with the barrier structure.

In one embodiment, the barrier structure includes a plurality of coppertraces disposed on an uppermost surface of the foundation substrate.

In one embodiment, the plurality of copper traces includes a chevronpattern.

In one embodiment, the barrier structure includes a patterned inkstructure disposed on an uppermost surface of the foundation substrate.

In one embodiment, the barrier structure includes a plurality of slotsto restrict flow of an underfill material used to form the underfillmaterial layer.

What is claimed is:
 1. A semiconductor apparatus, comprising: first andsecond semiconductor dies, each having a surface with an integratedcircuit thereon coupled to contact pads of an uppermost metallizationlayer of a common semiconductor package substrate by a plurality ofconductive contacts, the first and second semiconductor dies laterallyadjacent to one another and separated by a spacing; a barrier structuredisposed between the first semiconductor die and the commonsemiconductor package substrate and at least partially underneath thefirst semiconductor die; and an underfill material layer in contact withthe second semiconductor die and with the barrier structure, but not incontact with the first semiconductor die, wherein the underfill materiallayer is disposed on and over an uppermost surface of the barrierstructure at a location of a highest point of the uppermost surface ofthe barrier structure above the common semiconductor package substratebut is not on a portion of the uppermost surface of the barrierstructure underneath the first semiconductor die.
 2. The semiconductorapparatus of claim 1, wherein the barrier structure comprises aplurality of copper traces disposed on an uppermost surface of thecommon semiconductor package substrate.
 3. The semiconductor apparatusof claim 2, wherein the plurality of copper traces comprises a chevronpattern.
 4. The semiconductor apparatus of claim 1, wherein the barrierstructure comprises a patterned ink structure disposed on an uppermostsurface of the common semiconductor package substrate.
 5. Thesemiconductor apparatus of claim 1, wherein the spacing separating thefirst and second semiconductor dies is approximately 100 microns.
 6. Thesemiconductor apparatus of claim 1, wherein the first semiconductor dieis a memory die, and the second semiconductor die is one selected from amicroprocessor die and a system-on-chip (SoC) die.
 7. The semiconductorapparatus of claim 1, wherein the barrier structure comprises aplurality of slots to restrict flow of an underfill material used toform the underfill material layer.
 8. The semiconductor apparatus ofclaim 1, wherein the first and second semiconductor dies areelectrically coupled to one another by an embedded interconnectionbridge (EmIB) disposed within the common semiconductor packagesubstrate.
 9. The semiconductor apparatus of claim 1, wherein thebarrier structure comprises a plurality of runaway traces for excessportions of the underfill material layer.